The present invention relates to a new composition of matter, a thermal control composite comprising a polymer and an endothermic agent. The endothermic agent is distributed, dispersed and suspended within and throughout the polymer and cured to form a composite for use in insulating, thermoprotecting, heat absorbing applications on the one hand and heat maintenance applications of all types on the other.
All of the prior art known to Applicant teaches the use of endothermic agents in heat sinks wherein the endothermic agents are either coated, adsorbed or packed into various supporting structures.
For example, Applicant""s first patent U.S. Pat. No. 4,449,916; discloses an endothermic agent adsorbed onto the fibers of the fabric matrix.
Applicant""s second patent, U.S. Pat. No. 5,709,914 discloses an thermal storage compound packed into an open cell network, comprising natural, synthetic or metal fibers, spheres, particles, foams, or materials capable of being formed into a container suitable for enclosing and maintaining an item""s high heat.
There are two very serious drawbacks to the prior art. First, leakage of the endothermic or thermal storage compound to the surrounding environment can occur, if the physical integrity of the various underlying supporting structures is somehow compromised. Such leakage will diminish the effectiveness of the heat sink material and may even lead to the harm and destruction of the item or material the heat sink material is supposed to protect, particularly if the endothermic or thermal storage compounds are harsh and corrosive.
Second, the underlying structures upon which the endothermic or thermal storage compounds are coated, absorbed, adsorbed or packed tend to be stiff and inflexible. The further coating, absorption, adsorption and packing of endothermic or thermal storage compounds on and within such structures will cause them to stiffen even more. This stiffening of the material renders them entirely unsuitable in applications where the heat sink materials must be flexible and in certain situations light, thin and drapeable.
It is therefore an object of the present invention to provide a composition of matter that can act as a heat sink/heat shield, but which will resist leaking the endothermic compound into the environment, by eliminating any possibility of a compromise of the structural integrity of the underlying carrier or support structure in the heat sink material.
It is another object of the present invention to provide a composition of matter for applications requiring a heat sink/heat shield which needs to be thin, flexible, drapeable, and/or conformable, while simultaneously protecting and insulating against high or low heat environments.
It is yet another object of the present invention to provide a composition of matter for applications requiring a heat providing material which will be thin, flexible, drapeable, and/or conformable, while simultaneously protecting and insulating against extreme cold environments.
The aforementioned objects, as well as others, will be found in detail in the following written disclosure.
The inventive composition of matter is a flexible thermal control composite. Said composite comprises a polymer and an endothermic agent. The endothermic agent is dispersed, distributed, and suspended in the polymer. Thereafter it is cured to form a xe2x80x9cPxe2x80x9dolymer xe2x80x9cCxe2x80x9dontaining an xe2x80x9cExe2x80x9dndothermic xe2x80x9cAxe2x80x9dgent (PCEA) composite. This composite now has thermal control properties that make it suitable for a multitude of thermal control applications.
Natural or synthetic polymer may be softened or liquified by being (1) heated, (2) dissolved or (3) suspended in a plasticizer or solvent. When the polymer treated in any of these manners has an endothermic agent added to it, in very specific concentrations, distributed, dispersed, suspended therein and cured, a thermal control composite i.e. a PCEA is formed. Such PCEA is in essence capable of thermal control through its ability to absorb and store heat or through its ability to first absorb heat and then release it. It does so through the use of its endothermic compounds"" own inherent thermodynamic, physical and chemical properties, i.e. their latent heats of fusion, hydration, formation, decomposition, vaporization, sublimation, or its allotropic and phase change reactions; while simultaneously completely eliminating any possibility of leakage of its endothermic compounds into the environment, as said agents become an integral part of the PCEA overall physical structure.
Thus, according to the present invention there is provided a PCEA thermal control composite comprising a natural or synthetic polymer and an endothermic agent. The PCEA thermal control composite can be thin, as for example a thin or a thick film, or molded as a thick PCEA brick. When the PCEA is a thin film, then the effective distribution of the endothermic agents within said polymer is 0.0001 to 1.2 gram of endothermic or thermal storage compound per square inch of PCEA, the PCEA having a thickness of 0.05 to 2.0 mil. On the other hand, where the PCEA is a thick film or molded structure, then the effective concentration of endotherm will be 0.05%-60% by weight endotherm in PCEA.
Full details of the present invention are set forth in the following description and illustrated in the accompanying drawings.